Abstract
The present aim is to reveal the flow past a rotating ring which is immersed parallel to the mainstream. At first, we conduct field observations of a flying ring using a pair of high-speed video cameras, together with three-dimensional motion analyses based on their recorded images, which quantitatively reveal both paths and angular velocities of the flying ring. In addition, we conduct numerical simulations by a finite difference method, whose results suggest that the ring-rotation effect becomes remarkable for a rotation parameter Ω^* > 0.4. This suggests that the flight at Ω^* ≈ 0.4 is suitable.
